Solar photovoltaic power generation modules that convert solar energy into electrical energy may lose their power-generating abilities owing to, for example, defective connection between the modules or a reduction in quantity of sunlight due to the occurrence of a partial shadow in any one of the modules. A junction box for solar photovoltaic power generation (including a connector) serves to prevent the power-down of an entire system due to such loss of the power-generating abilities.
Here, a structure member for solar photovoltaic power generation such as the junction box for solar photovoltaic power generation has been required to have characteristics such as a high degree of low-temperature impact characteristic, tracking resistance, and flame retardancy because the structure member is typically placed outdoors. In addition, requisites for a material of the structure member have become more and more sophisticated in association with demands for the thinning and design of the structure member for solar photovoltaic power generation.
A polycarbonate-polydimethylsiloxane copolymer (hereinafter sometimes referred to as “PC-PDMS copolymer”), which is a polycarbonate-based material, has been known as a resin material having a high degree of low-temperature impact characteristic. However, when the PC-PDMS copolymer alone is used as a structure member for solar photovoltaic power generation, the structure member is poor in tracking resistance and is hence inconvenient unless the structure member is treated.
A resin composition blended with various compounds has been known for improving various characteristics of such polycarbonate-based material (see Patent Literatures 1 to 5).
Patent Literature 1 discloses a resin composition containing an aluminum borate whisker, and Patent Literature 2 discloses a resin composition containing an alloy of a polycarbonate resin and a polybutylene terephthalate resin. However, the resin composition of Patent Literature 1 is remarkably poor in low-temperature impact characteristic, though its rigidity improves because the whisker is used. In addition, there is a possibility that a harmful substance is generated at the time of the combustion of the resin because an organobromine compound is used. In addition, such alloy as disclosed in Patent Literature 2 also causes a reduction in low-temperature impact characteristic.
In addition, Patent Literatures 3 and 4 each disclose a resin composition containing a low-molecular weight silicone compound. However, even the incorporation of the low-molecular weight silicone compound cannot improve the tracking resistance of the composition, and a concern is raised about the following problem. An electrical contact becomes defective owing to a volatile component of the low-molecular weight silicone compound.
Further, in Patent Literature 5, an attempt has been made to blend titanium dioxide into a resin composition to improve its tracking resistance, but no investigations have been conducted on the surface treatment and impact resistance of titanium dioxide.